"The TV shots from the helicopter, the emergency crews coming in -- and at a school, a public school," said Rick Townsend, who lost his daughter, Lauren, nearly 14 years ago. "That seemed to bring it home to me more than some of the others have. This has been a lot tougher; it opened up so many memories."

And yet the difference -- the shockingly young age of the victims -- added another dimension to an ongoing story of violence that the Columbine families have long understood would be repeated too often.

"I knew that it was a very unfortunate fact that Columbine wasn't going to be the last, any more than it was going to be the first," said Brad Bernall, whose daughter, Cassie, died in the attack. "But I was just absolutely stunned, like I'd walked into brick wall and smacked my face on it. In this situation, it truly was the age and innocence of these kids that made it different."

The latest shooting prompted Tom Mauser to flash back to the awful scene in the Columbine library, where his son, Daniel, and nine others died. He grappled with imagined visions of the scene inside Sandy Hook and how those parents would deal with its horror.

Although he has appeared often in the media over the years to address the gun-control issues that became a passion after Daniel's death, he did little in the immediate wake of the Sandy Hook shootings.

"I was just too shattered," he said. "And I can't say that it was so much directly Columbine, that I was thinking of that day. It was just, 'Oh my god, it's come to this.' "

Still, he absorbs each new incident with a sense of inevitability.

"It's the nature of this country," Mauser said. "You don't change those things overnight, especially when you're doing virtually nothing about it. We're working on the edges -- bullying, more security at schools -- but we're not really doing anything major to prevent things like this, unfortunately."

He could digest media accounts of this tragedy only in small doses. When details about the victims began to emerge, the human side of the story proved more than he could handle.

"I watched Obama's speech last night," he said, "and as soon as he started reading off the names, I lost it. It's that personal connection thing."

The Sandy Hook shootings prompted unusually intense feelings for Townsend, as well. Some of that had to do with the way it reflected Columbine -- and some of it was the difference.

"It brought back a lot of the memories of things being reported that ended up not being true, the pictures of kids leaving the school, all those things that were very similar," he said. "At the same time, you know that these were little, defenseless kids.

Patricia DePooter, who lost her son Corey at Columbine, cried as she shared her feelings.

"There is nothing anyone can say to help them," DePooter said of the parents of the elementary school students. "It is a lonely, empty and numb place."

Still, time and support, especially from the local community, can help in the healing process, DePooter said. She recalled a time, a few months after Columbine, when shopping in the grocery store's dairy section brought her to tears after she saw a carton of chocolate milk, Corey's choice drink. Another shopper, someone DePooter recognized, saw her and stopped.

"We really didn't know each other, but she put her arms around me, and held me and cried with me," said DePooter, who envisions local community support helping the parents in Connecticut. "Their greatest blessing of all is the people who love them, in their town."

Both DePooter and Phyllis Velasquez, whose son Kyle died at Columbine, anticipate more collective soul-searching over the mass shootings as gun control, mental health, and even violent video games and movies again surface in the national conversation.

Both mothers said their faith in God, and the passage of time, has helped them through dark times.

"I think of my son and the others killed every day," Velasquez said. "I also can see the sunshine and hear the birds sing and live with the people who are around me again. But, it is a process. The only way I got to where I am today is with God's help."

Though Sandy Hook unfolded with its own incomprehensible set of circumstances, it also left Bernall to cope with one familiar, recurring set of emotions in a very difficult place.

"I call it being between a rock and a hard spot," he said. "The rock being, did this really happen? And the hard spot being, yeah, it really did. That is the one perspective that sews all these tragic events together, along with the very strong compassion that I have for the people that are left behind, hurting and aching and missing their loved ones.